The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
Conventional doorways of elevators may be equipped with photocells that provide information of people passing through a doorway. When a person passes close to a photocell, no light is received by the photocell and detection of a person either boarding or leaving the elevator may be made.
When the elevator experiences high traffic, more than one person may pass through the doorway at a time. Since already a single person may cause the blocking of the photocell, further persons passing through the doorway simultaneously cannot be detected by the photocell.
Load of an elevator car can be measured by mass on board the elevator car. A number of passengers aboard the elevator car may be estimated from the load by measuring a total load of the elevator car at arrival and departure to landing zone of the elevator and a minimum load during the stoppage of the elevator car. The number of passengers obtained in this way has inaccuracy due to an assumption that before any passengers aboard the elevator, passengers that are destined to the landing zone first leave the elevator car. Further inaccuracies may be caused by differences between estimates of the mass of a single passenger and the actual masses of the passengers.